Since the 1970's there have been several devastating oil spills as a result of oil exploration and drilling: Ixtoc, Exxon Valdez and, most recently, the Deepwater Horizon blowout off the coast of Louisiana. Ecosystems may survive and some may eventually recover from such oil spills. But the overall effects are far reaching and long-lasting. Scientists still see the effects of the Ixtoc spill on the crab populations in surrounding wetlands. All BUT ONE situation is an expected effect of the recent Deepwater Horizon oil spill in the Gulf of Mexico. That is: A) Tar balls buried beneath beach sand influence crustacean movements, habitats, and breeding patterns. B) The rapid extinction of top-level consumers in the Gulf food webs, such as sharks, dolphins, and sea turtles. C) Scrubbing efforts of surrounding wetlands interfere with an areas natural ability to regenerate plant growth. D) Deep sea oil plumes serve as a food source for bacteria, and in turn, the lower oxygen levels produce deep sea dead zones.